Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds meaningful behavioral context beyond the readOnly/idempotent/non-destructive annotations: uploads are ephemeral (24h), owner-scoped, and an expired or missing id both return as not-found. It also flags that this is a REST route rather than the JSON-RPC endpoint, helping the agent understand invocation behavior. No contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.